What Causes the Common Cold?
Common colds are caused by tiny organisms called viruses, which infect the mucous membranes of the nose and throat. These viruses are easily scattered about by the coughs or sneezes of a person with a cold. People nearby may catch the cold if the viruses enter their noses or mouths.
When you have a cold, your nose usually becomes stuffy and you sneeze a lot. Most colds last only a few days. They most often strike in winter and fall. People tend to stay together indoors more in cold weather than at other times, and this makes it easier for the virus to be passed on.
You can catch it from another person who is infected with the virus. This usually happens if you touch a surface that has germs on it — a computer keyboard, doorknob, or spoon, for example — and then touch your nose or mouth. You can also catch it if you’re near someone who is sick and sneezes into the air.
A cold begins when a virus attaches to the lining of your nose or throat. Your immune system — the body’s defense against germs — sends out white blood cells to attack this invader. Unless you’ve had a run-in with that exact strain of the virus before, the initial attack fails and your body sends in reinforcements.
Your nose and throat get inflamed and make a lot of mucus. With so much of your energy directed at fighting the cold virus, you’re left feeling tired and miserable.
One myth that needs to get busted: Getting chilly or wet doesn’t cause you to get sick. But there are things that make you prone to come down with a cold. For example, you’re more likely to catch one if you’re extremely tired, under emotional distress, or have allergies with nose and throat symptoms.